In marine propulsion systems it is generally desirable to provide a propeller thrust range of about 25-to-1 as well as provisions for reversing. For this reason, when a single gas turbine is employed as the prime mover in a ship propulsion system, it has been the practice to use a controllable and reversible pitch propeller. While such an arrangement provides the desired control and reversing, controllable and reversible pitch propellers are expensive and are not readily accessible if maintenance is required.
The primary object of the present invention, then, is to provide a marine propulsion system which utilizes a gas turbine engine and a fixed pitch propeller and yet provides a wide range of propeller speed and thrust control and provisions for reversing.